Soil erosion is the removal of fertile topsoil by water, wind, or human action faster than it forms; soil conservation is the set of practices that slow this loss and maintain soil fertility.
- Water erosion takes forms of increasing severity: sheet erosion (uniform thin removal), rill erosion (small channels), gully erosion (deep channels), and the badland or ravine topography of the Chambal valley.
- Wind erosion dominates in arid and semi-arid areas such as the Thar; deforestation, overgrazing, and faulty cultivation greatly accelerate all erosion.
- Conservation measures on slopes include contour ploughing (along contours, not down slope), terracing (steps on hillsides), and strip cropping; gully control uses check dams and bunds.
- Vegetative measures include afforestation, shelter belts (rows of trees against wind), cover crops, and crop rotation to maintain soil structure and organic matter.
- India's flagship watershed and soil programmes have included the Drought Prone Areas Programme and the integrated watershed schemes now folded into the PMKSY Watershed Development Component.
The sheet to rill to gully to ravine sequence, the Chambal badlands, contour ploughing and terracing, and shelter belts are standard agriculture and environment facts.
Sheet erosion (thin, uniform) versus gully erosion (deep channels); contour ploughing (along contour lines) versus terracing (steps); shelter belt (against wind) versus check dam (against water in gullies).
Topsoil loss by water (sheet, rill, gully, ravine) and wind; checked by contour ploughing, terracing, shelter belts, and afforestation.